1. Field of the Invention
The present invention concerns contact lenses which, to stabilize them dynamically, have at least one palpebral boss projecting locally from their external surface in their peripheral area, i.e. at a distance from their active central area.
Here "palpebral boss" means, in the usual way, a boss subject to the action of the eyelids each time the latter blink.
The required dynamic stabilization is precisely the result of this action.
The invention is more particularly, but not necessary exclusively, directed to contact lenses for centered optical correction, for example toroidal contact lenses and contact lenses for presbyopia.
2. Description of the Prior Art
European patent No. 0 042 023 concerns a centered optical correction contact lens including palpebral bosses.
However, this European patent gives no geometrical information on the palpebral bosses independently of their thickness, or height.
Experience shows that this geometry conditions the effectiveness of the palpebral bosses concerned, both in terms of the required dynamic stabilization and in terms of the comfort of the wearer of a contact lens including such palpebral bosses.
A general object of the present invention is to optimize this geometry.